<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>js调试</title>
		<script>
			var ar=["dog","CAT","pig","cananda"];
			var count=0;
			for(s of ar){
				if(s.toLowerCase().includes("a"))
				  count++;
			}
			document.write(`有${count}个`);
			//document.write("有"+count+"个");
		</script>
	</head>
	<body>
	</body>
</html>